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1091-專題演講-1091230-許鈺敏(交大電物)

演講活動
張貼人:李明芳公告日期:2020-08-18
  
Time1091230 (Wed.) 14:20~16:20
SpeakerProf.許鈺敏(SHEU, Yu-Miin)
國立交通大學電子物理學系/Department of Electrophysics, National Chiao Tung University
TitleAntiferromagnets can be more promising for spintronics
AbstractOn-demand spin orientation with a long polarized lifetime and an easily detectable signal is the ultimate goal for spintronics. However, there still exists a trade-off between controllability and stability of spin polarization, awaiting a significant breakthrough. Here, I will demonstrate switchable optomagnet effects in (Fe1−xZnx)2Mo3O8, from which we can obtain tunable magnetization (spanning from −40% to 40% of a saturated magnetization) that is created from zero magnetization in the antiferromagnetic state without magnetic fields. It is accomplishable by utilizing circularly polarized laser pulses to excite spin-flip transitions in polar antiferromagnets that have no spin canting, traditionally hard to control without very strong magnetic fields. The spin controllability in (Fe1−xZnx)2Mo3O8 originates from its polar structure that breaks the crystal inversion symmetry, allowing distinct on-site d-d transitions for selective spin flip. By chemical doping, we exploit the phase competition between antiferromagnetic and ferrimagnetic states to enhance and stabilize the optomagnet effects, which result in long-lived photoinduced Kerr rotations.[1] Moreover, we discovered that if the ferromagnetic state becomes the ground state by field cooling or by chemical doping, the huge optomagnet effect disappears. This implies that antiferromagnets can be more promising than ferromagnet/ferrimagnet for on-demand spintronics.
Reference: [1] Y. M. Sheu, Y. M. Chang, C. P. Chang, Y. H. Li, K. R. Babu, G. Y. Guo, T. Kurumaji, and Y. Tokura, Phys. Rev. X, 9, 031038 (2019)
PlaceB101, Gongquan Campuses, NTNU

最後修改時間:2020-12-25 AM 10:43

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單位簡介

本系的重點研究領域包括:凝態物理、光電與奈米科學、高能與粒子物理、軟凝態物理與生物物理、原分子光學物理、及物理科學教育等。本系前身為臺灣省立師範學院理化系物理組,成立於民國三十五年(1946年)本校創校之始。民國五十一年(1962年)本系獨立成系,民國六十三年(1974年)成立物理研究所碩士班,民國八十年(1991年)成立研究所博士班。長久以來,本系肩負著培育臺灣中等學校物理科師資的重任,但也不忘在物理學術研究上求新求進步。至今本系培育出的學術人才已有一位中研院院士及近百位中研院研究員及大學教授,各行各業的高科技人材更是不勝枚舉。民國八十三年師資培育法改制後,本系已升級為尖端學術研究、科技應用研發、及中學師資培育三者齊備的系所。

  • 國立臺灣師範大學物理系系友會
  • 系友會線上小額捐款
  • 徐有庠盃-臺灣青年學生物理辯論競賽
  • 國際物理奧林匹亞競賽
  • 公用場地與儀器設施預約系統
  • 學生實習專區
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